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ELPIS: Accelerated metal and dust enrichment in a proto-cluster core at z≈8

2025/10/13 by Umehata, Hideki, Tamura, Yoichi, Fudamoto, Yoshinobu +17
#Astrophysics of Galaxies (astro-ph.GA) #FOS: Physical sciences

paper · doi:10.48550/arxiv.2510.11788

Abstract

We present a study of the metal, dust, and molecular gas content in galaxies within the A2744-z7p9OD proto-cluster at z ~ 7.88. We focus on two galaxy groups, the Quintet and the Chain, which are covered by the ELPIS survey (The Emission-Line Protocluster Imaging Survey of the furthest overdensity beyond Pandora's Cluster Abell 2744). [C II] 158 um emission is detected in five galaxies, revealing molecular gas reservoirs with log(Mgas/Msun) ~ 9.0-9.6, while dust continuum at the observed frame of 1.26 mm is detected in three galaxies, yielding dust masses of log(Mdust/Msun) ~ 6.0-6.4, assuming a dust temperature of Tdust = 45 (+15, -15) K. The derived properties, including stellar-to-dust mass ratios of log(Mdust/Mstar) ~ -3 to -2 at log(Mstar/Msun) ~ 9, and dust-to-gas mass ratios of log(Mdust/Mgas) ~ -4 to -3 at 12+log(O/H) ~ 8, place these galaxies in an intermediate regime: higher than the very low ratios expected from supernova-driven dust production, but still below the levels attained once efficient grain growth dominates. These values indicate a transition phase of dust mass assembly, likely reflecting the onset of grain growth via metal accretion under accelerated evolution in the proto-cluster core.

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